Cockroach molt exoskeleton√Undergo the growth process√Exoskeleton will split down the back and force it to climb out from the old cuticle.√Takes six or seven molts for a newly hatched cockroach to reach sexual maturity.

Molt of exoskeleton:

Attachment of muscles on exoskeleton:√Join of muscle to part of exoskeleton√Allow muscle contraction√Move, flyExample: flexor and extensor muscle

The two main muscles: √Extensor tibiae muscle which causes the leg to extend√Flexor tibiae muscle which causes the leg to flex.√These tendons can be seen by removing the cuticle from one side of the leg in the joint region.

For instance, teacher can show a correct / incorrect way to keep the magnet and asks the students whether it is correct or not. If it is wrong, what should they do.

1.3 Magnets attract some materials

Demonstrate the ability of the lodestone to attract. Ask for explanations. Discuss natural and manufactured magnets.

Participants predict what will happen with sand. Record predictions.

Distribute sand to groups and test.

Groups report results.

Draw inferences through brainstorming.

1.4 Different uses of magnets

Ask participants how they might make a temporary magnet with a nail. Distribute nails and paper clips.

Participants experiment until they get the nail to pick up paper clips (after rubbing one pole of magnet along the length of the nail).

Participants provide explanation/reasoning and the different uses of magnet.

1.5 Magnets have different strengths

Ask participants to explore moving the magnetic objects along the tabletop without touching. Participants explore by placing various types of magnets a distance from the objects and under the tabletop.

Like all arthropods, German cockroach has a skeletal system on the outside of the body. According to Book Rags Website, the skeletal system is the framework of hard, articulated structures that provide physical support, attachment for muscles, and protection for the bodies of animals. It helps to support each organism and its limb in order to save from harm the internal organs. The attachment of muscle on skeletal system is essential to give functions in locomotion. Without this system, organisms would not move.

Lacking of internal skeletons, German cockroach wears its 'bone' on the outside in the form of an exoskeleton. This lifeless shell is placed atop the epidermis. “Exoskeleton is a chitin shell secreted by the mantle, a thin sheet of epithelial tissue that extends from the body wall.” (Boloman, Berg & Martin, 2005) It consists of three layers. The outermost layer is cuticle. “The cuticle is made up of a number of very thin laminations of chitin, arranged so that the fibers in each lamination run perpendicular to those above and below it, forming a cross-hatched pattern that gives great structural strength while allowing for flexibility”. (Starr, C., Evers & Starr, L., 2007) Everything that is visible on the outside of a cockroach which include the wings, skin, legs, and hairs. They are made of a single unbroken layer of cuticle.

The cuticle layer does not have cell on it. It is dead and unable to grow. The cuticle layer is made up of two parts. The waterproof epicuticle is placed in the outer part. It contains no chitin and is highly resistant to water solvents. Beneath this is the much thicker procuticle. It can be divided into two distinct layers. An outer exocuticle is laid below the epicuticle. An inner endocuticle which consists of a large number of layers of protein and chitin and chitin fibres laid down in a laminated pattern. Beneath the cuticle layer is the epidermis, which is made up of a layer of living cells that secrete the chitin making up the outer cuticle. Beneath this is the basal membrane that separates the epidermis from the internal body fluids and organs.

Photo cited from http://www.bio.umass.edu/biology/kunkel/bgmolt.html

“Exoskeletons restrict the growth of the animal, thus it must shed its exoskeleton (or molt) to form a new one that has room for growth.” (Huber& Maler, 1990) In order to undergo the growth process, the exoskeleton of cockroaches will be molted periodically. When the cockroach is ready to molt, the exoskeleton will split down the back and force it to climb out from the old cuticle. “The exoskeleton of a newly molted roach is white and soft, and is incapable of supporting the cockroach weight--the roach depends on its blood pressure to keep the soft cuticle from collapsing.” (Raven & Johnson, 1998) It takes six or seven molts for a newly hatched cockroach to reach sexual maturity. Once it reaches the adult stage, it will not molt again. Unlike most insects, which have a waxy coating on their exoskeleton to prevent dehydration, the thin layer of grease that cover the cockroach makes itself looks dirty. However, in reality, cockroaches are clean animals and put a lot of good effort to keep their cuticle clean of foreign matter.

“Through the attachment of muscles to the part of exoskeleton, cockroach is allowed to receive some forces as the contraction of muscle occurs.” (Hickman, C. P., Robert, L.S., Larson, A., I’Anson, H. & Eisenhour, D. J., 2006) The joint of the muscles to the rigid chitin exoskeleton enable cockroach to move. These muscles usually occur in pairs that operate to each other such as the flexor and extensor muscle which control forward and backward movement. Both of the muscles are attached to the same points of its exoskeleton to ensure the each movement can be coordinated. The extensor tibiae muscle which causes the leg to extend, and the flexor tibiae muscle which causes the leg to flex. These muscles pull on tendons which are attached to the tibia on either side of the joint pivot. These tendons can be seen by removing the cuticle from one side of the leg in the joint region

Photo cited from webs.lander.edu/.../periplaneta.html

Instead of this, the link of the muscle and skeletal system also allows cockroach to fly. The antagonistic movement of elevator and depressors muscle causes its wing to beat.

Part 2: Vulnerabilities that impact on cockroach

Cockroach becomes one of the insect that affects our quality of life. “Spray is natural or synthetic substances used by man to control pest organisms by disrupting some part of cockroaches’ life processes.” (Octopus, B., 2007) Literally, the term pesticide means to "kill pests." Spray contains chemicals that called acetylcholinesterase. Acetyl choline (ACh) is the nerve transmitter substance released by motor neurones to stimulate muscle contraction. The muscles relax (stops contracting) when the ACh is removed from the neuromuscular junction (NMJ) by the action of acetylcholinesterase. By inhibiting the cholinesterase the cockroach can no longer break down ACh in the NMJ and so its muscles lock up in a state of tetany (continuous contraction). It makes moving and flying impossible. Through controlling the muscle contraction within the skeletal system by chemical substance, cockroach can be easily killed. However, the chemical that released brings obvious disadvantage to our environment where it contributes a lot in air pollution.

Instead of this, many insects eat their cast cuticle (exuviae) after moulting. “Exuviate eating constitutes a meal, so the animal recycles its nitrogen content. Nitrogenous compounds (protein and chitin) are major components of the cuticle. The frequency of the behaviour decreased in newly emerged adults and varied between the sexes, males eating their exuviae less frequently than females.” (Mira, A., 2000) This may be due to the extra nitrogen endowment which females need for reproduction. Alex Mira stated that that over 58% of the nitrogen presents in the exuviae was recycled through the analysis of the frass produced after exuviae meals. This demonstrated that cockroaches digested nitrogenous compounds contained in the cuticle. Therefore, for those cockroaches which have approached directly to the spray may leave some of the chemical substance on their exoskeleton. They can be killed if eating their “skin” after molting due to the toxin substances left behind.

Learning outcomesAt the end of this lesson, pupils should be able to:1. identify various properties of certain material.2. record the result of experiment into table.3. answer the worksheet correctly.

Prior knowledgePupils studied about some things float and some things sink in Year 1. In Year 2, pupils learned to make a complete circuit when they learnt about batteries. Pupils studied the ability of some materials to absorb water in Year 3. They have also learn about different types of materials can absorb different amount of water and also the importance of these materials ability to absorb water. Besides, they have also studied the conductors and non-conductors of electricity. They have also learnt about the term “Stretch” in the topic “spring”.

Phase/Duration

Content

Teaching and Learning Activities

Remarks/ Resources

Introduction/ Engage(5 minutes)

• Short quiz• Identified the materials of the object that they get and do prediction on its properties. (complete Worksheet 1)

1. Teachers have done the group division before the lesson by distributing a small piece of paper with name list of group members and different post for each member. For example, group leader, secretary, speaker, 1/2 keepers (in charge of materials of that group).2. Teacher gives a brief explanation on the meaning of properties using the PowerPoint.3. Teacher does a short quiz by displaying the questions on the PowerPoint.4. The questions are:(a) Give one example of object that made of metal, wood, glass, rubber and plastic.[Expected answers –metal (metal ruler), wood (chair), glass (spectacle), rubber (balloon), plastic (plastic bag).]5. Teacher distributes one different object and a worksheet (Worksheet 1) to each group while another teacher giving the pupils instruction by asking them to do prediction on the various properties of the object that given with their group members. Then, pupils need to record their prediction on the worksheet.

Process skills:1. Prediction

Resources:LCD Projector, Laptop, Worksheet 1.

Development Explore(10 Minutes)

• Do experiment• Completing Worksheet 2

1. Teacher distributes all the materials needed for the experiment and Worksheet 2 to each group.2. Teacher gives pupils instruction of the experiment along with the PowerPoint show.3. Pupils need to test their prediction on various properties (conduct electricity, absorb water, can be stretched and allow light to pass through.) of the object and other equipments given by the teacher.4. Each group need to record their observation on Worksheet 2. Meanwhile, the teachers distribute each group 4 cards with the pictures of the objects they test with.

1.A “Speaker” of each group will come out and tell his peers about their group discoveries.2.Meanwhile, another member will also come out and paste the picture cards on the big table on the blackboard according to its properties.3.Afterward, each group needs to pass up their Worksheet 1 and 2.4.Teacher will discuss with the pupils on their conclusion.

Process skills:1. Classification.2. Communicate

Resources:Mahjong paper (table), blue tag

Elaborate(6 Minutes)

• Questioning activities

1. Teacher show children a picture of a car (the window of a car) and make discussion with them by asking some questions (show the pictures and questions using PowerPoint).Questions:(a) Suggest/ Say out one suitable material to make the window of the car. [Expected answer: Glass](b) What will happen if the material you suggested absorbs water and cannot allows light to pass through? [Expected answer: we will get wet, we cannot see the situation outside the car](c) Can you use this material to make spectacle? Give a reason. [Expected answer: Yes, because it allows light to pass through.]2. Teacher jot down students responses on the green board in form of mind-map.

1. All the pupils need to clean up and the “keeper” from each group needs to return all the materials to the teacher.2. Teacher ends the lesson by repeating the key concepts for today topic (properties of materials)3. Each pupil needs to answer the worksheet (Worksheet 3) distribute by teacher and hand up in the next lesson.

paste the pictures of animals according to their external feature into a table.

Description of the children:The text is prepared for the year three students. Students in this school are found weak in the English subject. They encounter big problem as reading English text where they unable to understand well about the content. One of the capabilities that most of the children in this class already have for reading text is encoding. They have learnt the consonant sounds in their previous lesson and this leads them to have the ability to read out the words properly.

However, there are some weaknesses occur among students in their reading skills. The students do not have enough vocabulary in English. “Learning vocabulary is a very important part of learning a language. The more words you know, the more you will be able to understand what you hear and read.” (S. Paul, 2001) Students need to make meaning before they able to understand the whole text. In order to do this, they should learn more words to avoid from limited vocabulary. It is important to develop their vocabulary as it will guide students to understand more about the text when going through it. Students will have the ability to learn in thinking critically. Besides, those students are found unable to read fluently. They should practice to read to become a good reader. Reading fluently will build up the self confidence of each student and thus, they can concentrate on their reading.

The text given is about the topic of external features of animals. The size of each picture in the text is bigger enough for the year 3 students to see. The external features of those animals are shown clearly in the pictures. Besides, the words and sentences are found easy to understand which is suitable to the level of year 3 students. Big fonts have been used in the text to ensure all the readers are able to read it properly. Most of the words that created are easy and simple which can extend students’ understanding through this topic.

Moral value:

Protect animals

Students learn to not hurt any animals which do not harm to us.

Students show their care to the animals.

Cooperation

Students cooperate with their peer to carry out their work during the activities.

Helping

Students learn to help those who are weak in their work during the lesson.

Previous knowledgePupils have learnt and approached to the animals during their daily life. They have the ability to imagine the part that can be found on the animal body. Besides, they can also explore the features through their pet such as dog, cat , bird. and known more about:

Step

Content

Teaching Learning strategy

Rationale

Remarks/Teaching aids

Set Induction5 minutes

Snail show:Teacher’s questions:1. What animal is this?2. Is it different from other animals?Why does it so special?3. What do you think the shell will feel like?4. Why the shell is important to snail?

Expected responses:1. This is a snail.2. Yes, it has a shell on its body.3. It is hard and strong.4. It protect the snail.

• Teacher brings the real model – 6 snails to the class.• Teacher divides students into 6 groups. There are 5 pupils in each group.• Teacher gives each group a snail.• Teacher requires pupils to observe the snails without touching and disturb them.• Teacher asks students question regarding to the snail after the observation.• Teacher leads students to the explanation of external features of animal during the discussion.

Real animals-snail is prepared by the teacher during the lesson in order to give a clearer picture about the topic and connect students to the real world. “Learning is a function of experience and the best education is one that is sensory-rich, emotionally engaging, and linked to the real world.” (W. Laverne & S. Judith, 2005) Teacher scaffolds the pupils by providing them to experience in the activity. This may keeps them to the long term memory about what they have learnt. Teacher keeps asking question to activate students using their previous background knowledge that contribute in the lesson.

√ 6 snails√ white papers

Moral values:

be kind to animals

cooperation

Skills:

Observing

Analyzing

Step 110 minutes

Learning vocabulary, reading text:Teacher’s questions:

How many animals can you find from this text?

What are the differences between these animals?

What are the external features from each animals? Why do you think it is important for them? (e.g.: butterfly)

Expected responses:1. Four animals.2. They have different types of external features.3. Butterfly has wings It uses them to fly.

• Teacher prepares some flash cards to show to the students.• Each flash card contains a vocabulary such as beak, feather.• Teacher pronouns each word followed by students.• Teacher gives a clear definition of each word after pronouncing it.• Teacher gives the text to each the pupils to read together in the classroom.• Teacher question pupils about the text given.

Teacher identifies the difficult words before reading. By using this way, teacher ale to ensure all the students can read and understand well about the text given. It can attract students to focus on the main ideas in the text. Teacher applies text as the teaching aid in order to practice the reading skill among pupils. Teacher also scaffolds students’ learning by questioning. “Questions permit people to check for understanding and obtain information.” (D. L. Daniel, 1990) This supports students in absorbing new knowledge and enriches their prior understanding.

•Teacher divides pupils into 6 groups where each groups has 5 persons.•Teacher provides some pictures of animals and a big table drawn on a manila card for each group.•Pictures are needed to classify the animals according to their external features and paste them on the table of manila card.•Each group pastes their work on the black board and discusses their work.

The pictures given encourage pupils to enrich their knowledge and practice the scientific skills of classification. They conduct the knowledge through this hand on activity. “Through activity, teachers believe they help their students to make sense of the concepts being taught.” (H. Jennifer, 2001) Teacher guides and scaffolds students by organizing interesting activity (classify and paste). It attracts the students’ interest within the topic. They work collaboratively with their peers and are given chances to communicate in front of class.

• 6 Manila cards• Glue• 10 pictures of animals.

Moral values:• communicate• cooperate

Skills:• classifying• communicating

Step 315 minutes

• Game:Different sound & external features that shown:√sound of cow√sound of cat√sound of chicken√sound of goat√sound of mouse√sound of frog

• Pupils are required to stay with their own group.• Every group is given name as group 1, 2...6.• Teacher plays the sounds of different animals using CD.• The group of pupils needs to use their part of body to act or show the external features of the animal based on the sound of animals that given when the teacher calls their group.• Pupils are only allowed to use their body language to represent the actions without speaking.• Group that presents well will gain 1 mark and for the group which fails to do it will get 0 marks.• The group that gets higher mark will become the winner.

In order to enable pupils to extend their existing levels of comprehension, interesting game is organized. It engages pupils to participate and enjoy in their learning process. A good teaching offers a lot of surprises for the children to go through in their learning process. They communicate with their peer groups in order to get highest mark. This game helps to recall their previous knowledge and apply them again during the game. Children try to remember and demonstrate the external features using their body language.

• Notebook• Sound of animals (CD)

Moral values:• Cooperate

Skills:• Listening• Communicating

Enrichment and remedial activities10 minutes

Exercises 1:Let us circle and colour•Circle and colour the picture of animals which have same external features with same colour in the farm.Exercise 2:Try it!•Fill in the blanks with correct words to answer the questions.

• Teacher gives the worksheets for pupils to complete.• Teacher explains about the works or exercises.• Teacher guides and assist the students who are weak in this topic.• Students are allowed to use dictionary to find the words that they are not understand.• Students discuss the answers with teacher.

• This is the section that is conducted by teacher to evaluate the children to see if they understood this topic. “In addition to these classroom techniques, exercises and homework can be used formatively if teachers analyze where students are in their learning and provide specific, focused feedback regarding performance and ways to improve it.” (B. Ann & M.Colin, 2002) On the other hand, it also gives opportunity for those students who do not fully understood about the topic to practice more through these exercises. Teacher is taking an informed and active role in scaffolding to guide students to develop their learning.

• Work sheet 1Let us circle and colour

• Work sheet 2Try it!• Dictionary

Skills:• Writing• Reading

Closure10 minutes

• Draw and labelFor example:chicken

• Teacher gives each pupil a paper.• Pupils are required to draw 1 animal that they like most on the paper given.• Pupils need to label the external features that can be found on the animals.• Teacher selects some students to read out their labels of external features.• Every student pastes their drawing on the board at the back of the classroom.

• Teacher lead students to recall and practice what they have learnt in drawing. She has changed another way to scaffold children. She requires the pupils to carry out their understanding by drawing rather than use all the words. Students usually feel bored when the lesson is coming to the end. Finally, they will not pay attention to what teacher is talking about. Thus, this is a way to attract their attention back to the lesson and participate in every learning process.